I get:
x86_64n
(probably need to quote '%{ARCH}\n' to get the \n to be a newline, heh)
I had the i386 package installed along side the x86_64 one; the same thing
happened when I started gnucash then, as well.

Here's the relevant output from 'rpm -V gnucash':
S.5....T /usr/bin/gnc-fq-check
S.5....T /usr/bin/gnc-fq-helper
S.5....T /usr/bin/gnc-fq/update
S.5....T /usr/bin/gnucash
S.5....T /usr/bin/gnucash-valgrind
S.5....T /usr/libexec/gnucash/overrides/gnucash-env
Just to be safe, I uninstalled gnucash and gnucash-doc, and then reinstalled
them. , after which verify produced the same results. I guess the size and MD5
differ on these because of prelinking?
After reinstalling I was able to run gnucash. I can't fathom why it worked after
the second reinstall but not after the first. I do now get the following warning
on starting gnucash, though:
gnc.bin-Message: main: binreloc relocation support was disabled at configure time.
Anyway, the problem is gone for me now, though I would like to know what caused it.